Treating a low: 15 grams, 15 minutes
Below 3.9 mmol/L, take 15 g of fast sugar, wait 15 minutes, check again. What counts as 15 g, what doesn't work, and what to do after.
A low — hypoglycemia, or a "hypo" — is the fast emergency. It arrives in minutes and it needs sugar now. This page explains how to recognize one, exactly how to treat it, and the common mistakes that slow treatment down.
Recognizing a low
A low is a blood sugar below 3.9 mmol/L. It can look like:
- shaking, sweating, looking pale
- confusion or slurred speech
- being suddenly irritable, angry or odd
- clumsiness, or going quiet
- drowsiness, being hard to rouse
It is caused by too much insulin for the food or the activity — and by alcohol, hours later. Untreated, it goes to seizure and unconsciousness. That is why it comes first.
The 15-15 rule
Below 3.9 mmol/L, Diabetes Canada says take 15 g of fast-acting carbohydrate — ideally glucose or sucrose as tablets or a solution, which beat juice and gels.
What 15 grams looks like
In practice, many people need more than 15 g — a Canadian study found an average of 32 g. Start at 15, recheck, and set your own amount with your diabetes team.
What does not work
The diet-drink mistake is the classic one at a family table, where both cans sit in the same fridge and look identical. If you keep pop in the house for treating lows, keep it clearly separate from the diet version.
If they can't swallow
Someone who is unconscious, having a seizure, or can't swallow safely must not be given anything by mouth. That is when glucagon is used, and when you call 911. See glucagon.
For the people around them
Sugar first, questions later. Always. If a person with type 1 seems confused, irritable or strangely quiet, the kindest thing is to offer juice, glucose tablets or regular pop straight away and ask questions afterwards. More on what family, friends and coworkers need to know is in the people section.